The present invention concerns a method and a device for feeding weft threads to the shed in airjet weaving machines.
As is known, in airjet weaving machines the weft threads are unspooled from bobbins by means of weft accumulators such as prewinders or similar, after which lengths of weft thread are taken from these weft accumulators and are fed to the shed by means of one or more main nozzles. The length of weft thread inserted into the shed is each time cut near the accompanying main nozzle and subsequently woven in.
In anticipation of the next thread insertion of the same weft thread, the cut thread end is held in the main nozzle by means of a weak air flow.
However, when a thread end is held in the main nozzle for too long, the top of the weft thread may be damaged, depending on the type of thread used. Such damage consists essentially of the thread being unravelled or even broken by the air flow exerted upon it for a certain period of time. As a result, a weft thread with a bad end or too short a weft thread is inserted into the shed, which results in a weaving error or a machine stop.
The problem mentioned above may occur during longer standstills of the weaving machine.